1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Hardware Random Number Generator support.
4 * Cavium Thunder, Marvell OcteonTx/Tx2 processor families.
5 *
6 * Copyright (C) 2016 Cavium, Inc.
7 */
8
9#include <linux/hw_random.h>
10#include <linux/io.h>
11#include <linux/module.h>
12#include <linux/pci.h>
13#include <linux/pci_ids.h>
14
15#define THUNDERX_RNM_ENT_EN 0x1
16#define THUNDERX_RNM_RNG_EN 0x2
17
18struct cavium_rng_pf {
19 void __iomem *control_status;
20};
21
22/* Enable the RNG hardware and activate the VF */
23static int cavium_rng_probe(struct pci_dev *pdev,
24 const struct pci_device_id *id)
25{
26 struct cavium_rng_pf *rng;
27 int iov_err;
28
29 rng = devm_kzalloc(dev: &pdev->dev, size: sizeof(*rng), GFP_KERNEL);
30 if (!rng)
31 return -ENOMEM;
32
33 /*Map the RNG control */
34 rng->control_status = pcim_iomap(pdev, bar: 0, maxlen: 0);
35 if (!rng->control_status) {
36 dev_err(&pdev->dev,
37 "Error iomap failed retrieving control_status.\n");
38 return -ENOMEM;
39 }
40
41 /* Enable the RNG hardware and entropy source */
42 writeq(THUNDERX_RNM_RNG_EN | THUNDERX_RNM_ENT_EN,
43 addr: rng->control_status);
44
45 pci_set_drvdata(pdev, data: rng);
46
47 /* Enable the Cavium RNG as a VF */
48 iov_err = pci_enable_sriov(dev: pdev, nr_virtfn: 1);
49 if (iov_err != 0) {
50 /* Disable the RNG hardware and entropy source */
51 writeq(val: 0, addr: rng->control_status);
52 dev_err(&pdev->dev,
53 "Error initializing RNG virtual function,(%i).\n",
54 iov_err);
55 return iov_err;
56 }
57
58 return 0;
59}
60
61/* Disable VF and RNG Hardware */
62static void cavium_rng_remove(struct pci_dev *pdev)
63{
64 struct cavium_rng_pf *rng;
65
66 rng = pci_get_drvdata(pdev);
67
68 /* Remove the VF */
69 pci_disable_sriov(dev: pdev);
70
71 /* Disable the RNG hardware and entropy source */
72 writeq(val: 0, addr: rng->control_status);
73}
74
75static const struct pci_device_id cavium_rng_pf_id_table[] = {
76 { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xa018), 0, 0, 0}, /* Thunder RNM */
77 {0,},
78};
79
80MODULE_DEVICE_TABLE(pci, cavium_rng_pf_id_table);
81
82static struct pci_driver cavium_rng_pf_driver = {
83 .name = "cavium_rng_pf",
84 .id_table = cavium_rng_pf_id_table,
85 .probe = cavium_rng_probe,
86 .remove = cavium_rng_remove,
87};
88
89module_pci_driver(cavium_rng_pf_driver);
90MODULE_AUTHOR("Omer Khaliq <okhaliq@caviumnetworks.com>");
91MODULE_LICENSE("GPL v2");
92

source code of linux/drivers/char/hw_random/cavium-rng.c